1. Fakultät Sozialwissenschaften, Technical University Dortmund, Dortmund, Germany
2. Centre for Economic Analysis - CenEA, Szczecin, Poland
3. Faculty of Law and Economics, University of Greifswald, Greifswald, Germany
4. IZA - Institute of Labor Economics, Schaumburg-Lippe-Straße 5–9, Bonn, Germany
5. Warsaw School of Economics, Warsaw, Poland